The accumulated epidemiologic and laboratory findings have suggested that some micronutrients may inhibit or prevent the process of carcinogenesis. Since these micronutrients may exert their actions at specific tissue sites, adequate target tissue concentration of the micronutrient may be critical for the prevention of cancer and/or precancerous conditions. In order to define the role of micronutrients in cancer prevention, it is, therefore, important to study the micronutrient content of various tissues in humans, especially those with normal, premalignant lesions, and cancers. In the proposed study, we will determine the content of various micronutrients, including vitamin A, beta-carotene, lycopene, and vitamin E, in plasma, buccal mucosal cells, skin, and cervical tissues of normal individuals, subjects at high risk, and cancer patients. We will also compare the difference in micronutrient content between normal, precancerous, and cancerous tissues of same cancer patient as well as between cancerous tissues from cancer patients and normal tissues from matched controls. Because tissues other than blood and buccal mucosal cells are difficult to obtain in humans, we will, therefore, investigate whether the micronutrient content of plasma and/or buccal mucosal cells can be used as an indicator for assessing the micronutrient status of other issues. This will be accomplished by investigating the relationship between the micronutrient content of these two tissues and the micronutrient content of the target tissues such as skin and cervix in cancer patients and non-cancer individuals. The analytical procedures for analysis of the above micronutrients are well established in our laboratory. An extensive quality control/quality assurance (QC/QA) program will be followed in order to assure the accuracy of the analytical data. Our laboratory has been consistently rated as one of the most accurate analytical laboratories among the participants in the National Bureau of Standards sponsored QC/QA program for analysis of vitamin A, beta-carotene, and vitamin E since 1984. Our group at the University of Arizona Cancer Center is multidisplinary and has the necessary expertise to conduct the proposed study. We plan to complete the investigations in 4 years.